[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20160701102018.GB8787@gmail.com>
Date: Fri, 1 Jul 2016 12:20:18 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Borislav Petkov <bp@...en8.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>, Franck Bui <fbui@...e.com>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -v2 2/2] printk: Add kernel parameter to control writes
to /dev/kmsg
* Borislav Petkov <bp@...en8.de> wrote:
> On Fri, Jul 01, 2016 at 11:04:13AM +0200, Ingo Molnar wrote:
>
> ...
>
> > So the most robust way to define such bitfields is via a pattern like this:
> >
> > enum devkmsg_log_bits {
> > __DEVKMSG_LOG_BIT_ON,
> > __DEVKMSG_LOG_BIT_OFF,
> > __DEVKMSG_LOG_BIT_LOCK,
> > };
> >
> > enum devkmsg_log_masks {
> > DEVKMSG_LOG_MASK_ON = BIT(__DEVKMSG_LOG_BIT_ON),
> > DEVKMSG_LOG_MASK_OFF = BIT(__DEVKMSG_LOG_BIT_OFF),
> > DEVKMSG_LOG_MASK_LOCK = BIT(__DEVKMSG_LOG_BIT_LOCK),
>
> Agreed with so far, I'd only drop the "_MASK" thing and make it even
> easier on the eyes:
>
> enum devkmsg_log_state {
> DEVKMSG_LOG_ON = BIT(__DEVKMSG_LOG_BIT_ON),
> DEVKMSG_LOG_OFF = BIT(__DEVKMSG_LOG_BIT_OFF),
> DEVKMSG_LOCK = BIT(__DEVKMSG_LOG_BIT_LOCK),
> };
It's just a nit, but generally it's nice to know the character of such values -
i.e. in case that it's a bit mask that has to be used with bit ops. That's more
important IMHO than brevity. This means that possibly buggy code like this stands
out immediately:
if (devkmgs_log == DEVKMSG_LOG_MASK_ON)
while this one:
if (devkmgs_log == DEVKMSG_LOG_ON)
might slip through.
But no strong feelings either way!
Thanks,
Ingo
Powered by blists - more mailing lists